HOUSTON (AP) - Case Keenum became the Football Bowl Subdivision's career leader in total offense on Saturday, throwing for 376 yards and tying his career high with six touchdown passes in No. 21 Houston's 63-28 win over Marshall.

The senior quarterback needed 130 yards to eclipse the record (16,910 yards) set by Hawaii's Tim Chang from 2000-04. He moved past Chang on a 30-yard pass to Justin Johnson with 3:56 left in the first quarter.

Keenum completed 24 of 28 passes--15 in a row during one stretch--and also crept closer to the major college football career records for passing yards and touchdown throws. He needs 802 passing yards to move ahead of Chang's record (17,072) and five TD passes to eclipse the mark (134) set by Texas Tech's Graham Harrell from 2005-08.

Houston coach Kevin Sumlin awarded the game ball to Keenum at midfield, where the Cougars gathered behind him. Keenum turned to his teammates and hoisted the ball.

The Cougars (7-0, 3-0 Conference USA) have matched their best start since the 1990 squad won its first eight games, and this season is starting to look a lot like that one.

Houston finished 10-1 and led the nation in total offense (586.8 yards per game) that year, with David Klingler guiding the fast-paced run-and-shoot. Houston once again boasts the country's top offense (604 yards per game) and Keenum is producing numbers just as eye-popping as Klingler's were 21 years ago.

A.J. Graham threw two touchdown passes and ran for a score for Marshall (3-5, 2-2), which lost handily despite gaining 506 yards and winning possession time by 24 minutes.

Houston led 35-14 at halftime, and four of its five touchdown drives took less than 90 seconds.

Keenum was nearly perfect in the first half, completing 19 of 21 passes for 295 yards and four touchdowns. He also never faced pressure from Marshall defensive end Vinny Curry, Conference USA's sacks leader.

On the Cougars' third play from scrimmage, Keenum found Patrick Edwards down the sideline for a 70-yard touchdown.

Officials initially threw a flag, ruling that Edwards stepped out of bounds before making the catch. Sumlin challenged the call and upon video review, officials ruled that Edwards was pushed out by a Marshall defender and the touchdown was allowed.

The Thundering Herd took five minutes off the clock with a 12-play, tying touchdown drive later in the first quarter.

Keenum set the total offense record on his next pass, hitting Johnson in stride over the middle. Keenum went 5-for-5 on the drive, and Tyron Carrier made a 12-yard touchdown reception. Carrier has a catch in 46 consecutive games, the nation's longest active streak.

Carrier was among the first players to smack hands with Keenum on the sideline when his milestone was announced to the crowd.

Marshall tied it again, but Charles Sims broke a 51-yard run to the Herd's 18, then scored on a 6-yard run. Michael Hayes, Houston's leading rusher, turned two short passes from Keenum into long touchdowns later in the second quarter as the Cougars stretched the lead.

The Herd drove to the Houston 1 late in the half, but the Cougars' defense stopped Tron Martinez on fourth down on the final play before the break.

Graham scrambled for a touchdown on Marshall's first series of the second half. Keenum promptly found Carrier for a 43-yard gain, then threw a 17-yard TD pass to Johnson to cap another lightning-fast scoring drive.

Houston linebacker Sammy Brown deflected a Graham pass, linebacker Derrick Matthews intercepted and returned it for another Houston touchdown to make it 49-21.

Cougars' defensive end Kelvin King returned an interception 69 yards, and Keenum threw a TD pass to E.J. Smith, sending Houston over 50 points for the third time in four games.

Keenum has won 19 consecutive home starts and has 66 touchdown passes with only nine interceptions in that span. He's won 31 games overall as a starter, second only to Boise State's Kellen Moore (45) among active FBS quarterbacks.